The need for preservative devices used during transportion of fruits and vegetables is becoming more important. This need is becoming greater as the fruits and produce consumed by city dwellers are being shipped from greater and greater distances.
It is known to use sulfur dioxide generators when shipping grapes packaged in containers. The problem with this method is that the sulfur dioxide generator has a strong decolorizing affect on the grapes. The decolorizing of the grapes makes it difficult to market grapes to the consuming public.
It is also known to spray aqueous solutions of hypochlorites into the containers utilized for transport and handling of asparagus. This technique is quite complex due to the poor control of the aqueous concentrations of hypochlorite. When the concentration of the hypochlorite is too high, the asparagus is attacked and spoiled. Furthermore, high concentrations of aqueous hypochlorite pose a corrosion problem in metal containers.
U.S. Pat. No. 2,071,625 (Haas et al) is directed to a method of preserving packaged bakery products. Haas et al is directed to bakery products susceptible to the growth of microorganisms. Haas et al disclose that the bakery product is enveloped in a wrapping material which is treated or impregnated with a harmless compound that liberates a germacidal gas. The germacidal gas is free chlorine. The material which generates the chlorine is preferably chlorazene or chloramine-T and dichloramine or dichloramine-T. This reference also discloses that hypochlorites of sodium, potassium and calcium are suitable as a source of chlorine.
U.S. Pat. No. 4,094,119 (Sullivan) discloses a method of making a product for dispensing a volatile substance. The product includes a polypropylene backing layer, a non-woven material forming a reservoir layer, and a microporous polypropylene layer covering the reservoir layer. All three of the layers are joined around the peripheral edge portions. The reservoir layer stores the volatile substance.
U.S. Pat. No. 4,411,918 (Cimino et al) discloses an apparatus for preserving food by generating a preservative gas. The gas generating device comprises a basin-like main container and an auxiliary container located at the interior of the main container. The main container carries a solid chemical reagent. The auxiliary container carries a liquid chemical substance. The gas generating device is placed within a produce storage or transport receptacle. The preservative gas is generated when an operator pierces the main auxiliary containers, which allows the liquid chemical substance to react with the solid chemical substance. The preservative gases disclosed in this reference include carbon dioxide and sulfur dioxide.
U.S. Pat. No. 4,528,228 (Clevenger) discloses at atmosphere control-cushioning pad for fruits. The pad comprises an upper and lower sheet, which are joined together at their peripheral edge portions, and a cushioning material is enclosed between the upper and lower sheets. The cushioning material may include a chemical composition. For example, the chemical composition can be calcium hydroxide which absorbs carbon dioxide, or potassium permanganate which oxidizes ethylene. Calcium chloride is also suggested because it absorbs water and assists in the cushioning function of the pad by expanding.